SISON, BASTARD-STONE PARSLEY, in botany: A genus of plants belonging to the class of pentandria, and to the order of diogynia; and in the natural system arranged under the 45th order, umbellata. The fruit is egg-shaped and streaked; the involucre are subtetraphyllous. There are seven species; the amomum, inundatum, segetum, verticillatum, salum, canadense, and amni. The four first are natives of Great Britain. 1. The amomum, common barbastard parsley, or field stonewort, is a biennial plant about three feet high, growing wild in many places of Britain. Its seeds are small, striated, of an oval figure and brown colour. Their taste is warm and aromatic. Their whole flavour is extracted by spirit of wine, which elevates very little of it in distillation; and hence the spirituous extract has the flavour in great perfection, while the watery extract has very little. A tincture drawn with pure spirit is of a green colour. The seeds have been esteemed aperient, diuretic, and carminative; but are little regarded in the present practice. 2. The inundatum, least water-parsley. The stem is about eight or ten inches high, branched,
Sistrum, and creeping: the leaves, below the water, are capillary; above it are pinnated: the umbels are bifid. It grows in ditches and ponds. 3. Segetum, corn parley, or honeywort. The stems are numerous, slender, striated, branched, and leaning; the leaves are pinnated; the pinnae are oval, pointed, and serrated, six or eight pair, and one at the end; the umbels small and drooping; the flowers minute and white. It grows in corn-fields and hedges. 4. Verticillatum, verticillate fison, has small leaves in whirls, and capillary; the stem is two feet, with few leaves; the common umbel is composed of 8 or 10 rays, the partial of 18 or 20; both involucra are composed of five or six oval acute foliola; the flowers are all hermaphrodite, and the petals white.